While at the Lewis Ginter Botanical Gardens here in Richmond, I’ve been evolving some Orchids. You can see me going through part of the process in that video there, but here’s the phylogenetic tree of the flowers as well. At the 2nd generation the bees are introduced, along with ‘bee vision’ which is a red filter in our case. Bee’s actually see far more colors than people can (especially the ultraviolet) so they would probably see things that looked more blue or purple, but the red filters worked well in our case. If you look up ‘what bee’s see’ or ultraviolet photos of flowers, you can see a more realistic depiction of what a bee would see when they look at a plant. This should also give you an idea
For us, the colors blue as well as darker colors in general stand out a lot more than something like red, which would appear invisible. The flowers also began to look more like bees, as is the case of the actual bee orchid, a flower which has evolved to look so much like bees that actual bees try to mate with it and get stuck with pollen instead.
I’ve included a ‘bee vision’ version of the tree as well, to give you an idea of how the flowers looked through the hand lenses. You can see how the very first generation before the bee’s are introduced to the game have almost invisible flowers.